Tractor chain



Aug. 2, 1927. 1,637,777

-H. Y. LAW

TRACTOR CHAIN 4 Filed Nov. 24 1920 5 Sheecafheet,2

J fm H mm11 Z7 j@ li n Mmm inamfal` Aug'. 2, 1927.

. A Vf-1,637,177- 1 'UNITEDSTATI-:sl PATENT. OFFICE. ,a

HENRY Y. LAW, or MERCED, cALmonNm. :unseren CHAIN.

Appfoation led :November 24, 1920. Serial o. 426,134.

This invention relates to endless chain tracks fdr tractors and thelike.

The object of the invention is to overcome well recognized defects whichare in- 5` herent inall tracks heretofore in use, and also to. improvethe operation of the track, and to increaseI the strength and wearingqualities of the same.

In all prior structures of this type the links have been pivotallyconnected together at their ends, and the rail surfaces have beendisposed between the pivot points. The disadvantage of this is found inthe fact that unless the sprocket wheels are elevated above the loadcarrying trucks, so as not to` sustain any load, the links in passingaround the sprocket wheels will vibrate the latter and will also diginto the ground. Where the.

sprocket Wheels are used to sustaina portion of the load, then a linkwill be carrying considerable weight when it is in a tilted posi-y tion,aboutto pass around a sprocket wheel. Practically all successfultractors make 4use .of load carrying devices between the sprocket 25wheels and elevate the latter so that they are not required to supportany of the weight of thetractor.

Some attempts .have been made to dispense with load carrying f trucksbetween the sprocket wheels by constructing the links so i that they donot flex inwardly, but all of these attempts have been unsuccessful forthe reason that the sprocket wheels then have to serve as load carriersand theaction ofthe tilting links is such as to vibrate the wheels andcause the links to dig into' the ground and otherwise interfere with thesmooth operation of the track. y

My new track is so constructed that any particular link always has itsshoe, fully and completely on the ground in a horizontal position aslong as the related rail is su porting any weight. It is not until aftert e rail is relieved of its load that the link starts to ex and onvtheother end of the track the shoe is always in horizontal osition on thegroundfbefore the sprocket w eelrides on to 'the related rail. Thisaction is due to the fact that the links are not cennected'together attheir ends, but rather at points set in from each end. The rail surfacesextend from the projecting end of the link to the point of articulationand that portion of the llink between the points of articulation has .55no rail. surfaces. In passing around the sprocket wheel the only partofthe link to contact with the rim of the wheel is 'the innerthesprocket wheels. I, therefore, provide means for preventing the linksfrom flexing inwardly so that all of the track on the ground will servelto support the load.

Instead of using the conventional pivot pins I employ rocker lugs whichform the pivots for the links. Thereb all friction surfaces areeliminated and t life of the track .is greatly increased. The links areheld together laterally by means. of arcuate guides at each end of thelink.

The Various links of the track are constructed so that earth and similarmatter is readily squeezed out and does not tend to clog the parts andprevent their proper functiomng. The manner in Awhich the parts roll onone another does away with considerable loss by. friction and thereforewith wear.

With these and incidental objectsin view, the invention consists incertain novel features of construction and.` combinations of parts, theessential elements whereof are recited in the appended claims and apreferred form of embodiment of which is described'in detailhereinafter'v and illustrated in the accompanying drawings which form apart of this specification.

Reference being had to the accompanying drawings forming apart of thisspecification:

Figure 1 is a view in side elevation showing two supporting wheels ofthe tractor with a 1sleciiion of my improved track between these W ee s.

Figure 2 is a view in plan'of severallinks v as when assembled. f 1 1li;igure 3 is aview in plan of asingle track 1n f Figure 4 is a view inside Aelevation of the same. i

Figure 5 shows a perspective view of two of the links.

Referring to corresponding parts in the several views by the samenumerals of reference: 1 denotes a driving wheel'and 2 an idler wheel,these wheels being held in spaced-relation by means 4of the adjustablerods 3. My improved track passes around the wheels 1 and 2 and is formedof links which are denoted in general by 5. Each of these links is ofthe same construction vand comprise an\extension tread 6. Extendingoutwardly fromeach side of this tread, are segmental portions 7 and 8which are symthe ends o f thevlugs are positioned withinV denoted by A,while the center of the arcuate surface 8 of extension 8 is denoted byB. On.thel inside of the extension members 7 and 8 are formedcurvedsurfaces 9 and 10 resp'ectivelyfhaving their centersat B and Arespectively. -Y l Formed on the outer ends of the members 7 and 8 arelugs 11 and-12. These lugs have their outer ends shaped. on arcs, the

. centers of which are in the points A and B respectively. Thel radii ofthe -arcs 13 and 14 are slightly less than those of the surfaces 9 and10 .so that when assembled the arcs on the adjacent arcuate surfaces 9and 10. Extending outwardly on oneside of the arcs 9 and 10 area'wings"15 and 16,the outer edges of/vwhioh are also arc shaped and have and yetpermit slightlygreaterl radii thanthe outer surfaces of the arcs 7 and8. These'wings form .guides for contact with the outside of lugs 11 and12 ,td prevent lateral movement of the links when'they are assembled.'It will be noted that the' tread 6 is hollowed out as shown at 17, thishollow being provided in\ner previously described, and the track .mov

order to secure a greater length of the wings t e'tassembhng of thelinks.r

The distance frmA the lower 'edge of the wings tothe bottom of therecess 17 is greater than the width across the outer ends of @he lugs 13-and 14, so thatl inlassembling, the are held at such anangle that thelug 3 may enter the recessj'17 ioutsideof the wing1 5. Then by a sidemovement,` the lug is moved past'the lower end ofthe and strai h tenedout to bringthe lug mto the slt ormed between the wing 15 guide surface9.

' 'the radii ofw hich are in the centers A an The two segmental portionsof the link are connected across their upper ends b of the bridge member20.* This mem r com-` prises the olset'curved portions 21 and 22(Brespectivel In' he center of theibridge is an upwar projection 23 whichformsa driving wh This tooth is connected by the' curved portions 24 and25 with the prtions 21 'and 22.Y When the-links are engaged by thewheels, thecurved portion 24.-

,of one link lies adjaceng the curvedportionI '25 ofthe adjacentlink,'forming a substan-j tially semi-circular recess for engagementwith the driving pins 'The upper surfaces of the extension members 7 and8 formlrail surfaces 26 and 27 on which the supporting wheels tends tosink-"into the wheels roll. Thelunder surface 29 yof thebridge 20 isplaced somewhat above the rail surfaces just mentioned and I provide onthe rail surfaces small abutmelt pads 28 for contact with the undersurface of the bridge.

Extending outwardly from the inside surfaces of the members 7 and 8arerocker lugs 30 and 31. These lugs have curvedcontact surfaces 32which roll on the corresponding surfaces of the lugs of. the adjacentlinks. This curved surface passes through the centers A and B and is soselected that when the linksv are bent withv reference to eachl Lotherthey move substantially as though the linkslwere pivotally mounted aboutthe points A and B. The curve of 'each of these lugs is extended underthe bridge 20, and'it is this part ofthe curve which contacts with thelug of theassociated `link. This construction gives a width of contactwhich is twice that of the lugs themselves. The inner point of the lugsis substantiall inthe same' .plane as the surface 29 andas t -e lug ofone link extends under the bridge of the adja- Icent link, I providethesmall notches 40 to give clearance. The supporting wheels 1 and 2 are ofthe lanterntype comprising the two .discs 36 betweenvwhich areheld pins37.

The discs are spaced apart adistance slightly greater thah the widthofthebridge an the thickness of 'the discs in substantially the sameasthe width'of the surfaces 26 -and 27. lapse, the links are assembled in:the man-- the^`1inks passes over the two towards recess of each otherinorderto give .sullicient slack i so that the two end links of the trackmay -bendat an angle to each other to permit the lateral movementwhereby the lugs'll and 12 may be entered back o and-16, when'the wheelsare moved apart to hold the links straight. The vtrack between the twosupportingbvheels which rest on the ground tends, to pressed upwardly'between di portion of the track dlrectly 'under' the aterextent than'that between the' wheels. ith-thefim roved construction here ustrated,the hnk'sJIrxn` a between; the

groundtoa the wings 15 e' two wheels,)or -in'other words that 1 whiswhereby. amending of the fm1: s

Proven the Y the supporting wheels `carries a uniform loadbeingrstraight between Aover all portions. The action whereby thisAtruss'eiect. is secured is obtained by contact of the pads 28 with thesurfaces 29 outsidel of the pivot points yof, the links. The roller'surface-formed bythe surfaces 26 and 27 `is a substantially straightline. This surface 'a perpendicular.`

always extends b'eyglngd plane' through the a Aof rotatlon `of the-wheels so that the latter do not'tendtov climb or drop about the timethev links break this action is of links each consisting reaches the endof the surface 27 of link 53. j

The upper corners of wings and 16 are out away at an angle as shown at38 and 39 and ,during the time the links move.

around the wheels these beveled ends are seated on 'the periphery of thediscs. There being no rail surfaces between these beveledl ends, thecentral portion of the link when the latter is flexed is free to moveinwardly toward the center of thesprocket wheel, so that while the linksbetween the wheels have the tread surfaces tangent to the peripheriesofthe discs, the plane of the same surfaces of the links passing aroundthe wheels falls within the periphery of the discs. This allows thetread surfaces tofbe picked off of the ground without anyprtion thereofprojecting outwardly from the center of the wheel a greater distancethan when the links form in a straight line between the two wheels. Thisaction allows the links to pass on to the supporting wheels without theedge of the tread portions digging into the earth or raising the wheel.The latter action would invariably take place where the rail surfacesare formed between the pivots. By allowing the center to move inwardlytowards the axis of rotation, overcome and the links enter and leave thewheels withl a smooth action'.

Having thus described my invention, I claim as new and wish to cover byLetters Patent:

1. A tread chain comprising a plurality of two offset spaced arcuatemembers, a tread plate connecting the lower ends ,of

,the arcuate members, a

bar connecting the upper ends of the arcuatehmembers, rocker contactlugs formed on the upperv inside corners of said members, said lugsbeing adapted to engage the corresponding lugs of adjacent links topivotally connect them, said members having arcuate grooves on theiropposedfaces, extension lugs formed on the outer ends of said membersfor engagement by the grooves of adjacent links, rail surfaces on theupper sides of said members and lugs laterally displaced from the railsurfaces and adapted -to contact with the under surfaceof the saidconnecting bar to .prevent flexure of the chain in an upward direction.2. An endless chain track made up of articulated links,

each having a central, longitudinal web portion overlyin .the treadsurface, and a lateral projection at each end of the shoe extending inopposite directions and forming rocker lugs adapted4 to be engaged bycorresponding lugs on adjacent shoes, and an arcuate guide member formedin the transverse plane of each lug, each link having a projecting endportion formed with a curved surface to fit into the arcuate guidemember of the adjacent link.

3. In combination with a sprocket wheel having spaced side plates andpin teeth eX- tending 'between them, an endless chain track comprising aseries of articulated links, each link formed with extension railsurfaces at its opposite ends to engage the lplates of said. sprocketwheel, and an intermediate centrally arranged upstanding web portionAforming atooth to engage the pin teeth ,of the sprocket wheel, said webportion being cut away on its underside in the plane of the railsurfaces, adjacent linksbelng overlapped at 'their ends, on theoverlapping ends of thel links to extend under the Web portion of theadjacent link, whereby to lock the track against upward flexing.

In testimony whereof I aiiix my signature.

. HENRY Y. LAW.

and a portion

